Pressure accumulator-type liquid spraying device

ABSTRACT

An accumulator-type liquid sprayer includes a piston arranged in a cylinder, a piston guide extending through a passage extending therethrough in an axial direction of the piston, so as to be engageable with, and disengageable from the piston, cooperating with the piston and the cylinder to form a space region for sucking and pressurizing a liquid, a check valve for opening a suction port of the cylinder during suction of the liquid, and a hollow stem slidably fitted with an outer side of the piston in a liquid-tight manner and engaging with an end portion of the piston guide. A first resilient member urges the piston guide against the piston for maintaining a closed state of the passage in the piston, and a second resilient member urges the piston against the piston guide for adjusting a spraying pressure of the liquid. A stopper is arranged in the cylinder, for positioning the piston before the content is sprayed to provide increased contact surface pressure so as to maintain the closed state of the passage. The piston has an end portion which can be brought into contact with the stopper, and which is formed with an annular recess extending along an outer peripheral edge of the end portion.

BACKGROUND ART

1. Technical Field

The present invention relates to an accumulator-type liquid sprayer, andaims to effectively prevent leakage of the liquid within a cylinder ofthe sprayer.

2. Prior Art

As a sprayer for spraying finely atomized liquid such as lotion, cologneor perfume, aerosol-type sprayers are widely used wherein dispersedfluid is filled in a container together with pressurizing medium. Thistype of sprayer is relatively expensive in terms of production cost, andrequires discharge of the pressurizing medium by piercing a hole in thecontainer when it is discarded, since in many instance the pressurizingmedium remains in the container even after the dispersed fluid has beenfully consumed. Thus, the disposition of the container is troublesome,besides that discharge of the pressurizing medium into atmosphere maylead to environmental contamination.

Therefore, it is a recent trend to reevaluate accumulator-type liquidsprayer which does not require pressurizing medium as used in theaerosol-type sprayers, and which sprays the content under an elevatedinner pressure obtained by a couple of pumping actions of the dischargehead. In this connection, reference may be had to a pump-type sprayer asdisclosed in U.S. Pat. No. 5,638,996.

Typically, an accumulator-type liquid sprayer includes a cylinder havinga suction port communicating with interior of a container and fixedlyheld at a mouth portion of the container, a piston arranged in thecylinder, a piston guide for opening or closing a passage for passingtherethrough a liquid to be sprayed, by engaging with, or disengagingfrom the piston, a hollow stem for holding one end of the piston guideand having another end in engagement with a back face of the pistonthrough a resilient member, and a pressurizing cap in engagement withthe hollow stem and having a nozzle for discharging the content flowingthrough an internal passage, wherein the pressurizing cap is repeatedlyapplied with intermittent load for sucking and pressurizing the contentand thereby achieving a pumping action for continuously spraying thecontent.

In this instance, the piston and the piston guide are sandwiched fromboth sides and thereby held by resilient means (inner pressure adjustingspring and sucking/pressurizing spring). The force of the resilientmeans is adjusted so that the piston and the piston guide are in contactwith each other when the pressurizing cap is not applied with a load, tothereby close the passage for passing the liquid therethrough.

Incidentally, in order to reduce the load to be applied to thepressurizing cap upon spraying the content and thereby realize sprayingunder a smooth pumping action, it would be effective to lower theresilient force of either one of the inner pressure adjusting spring andsucking/pressurizing spring, among the resilient means. In thisinstance, however, since the contact pressure between the piston and thepiston guide is reduced, liquid leakage may occur in the cylinder,making it difficult to achieve an efficient spraying of the content.

In the case of accumulator-type liquid sprayer, furthermore, since thepiston has a substantially flat end surface, if this flat end surface isbrought into contact with a stepped surface provided in the cylinder soas to restrict displacement of the piston within the cylinder, the rootportion of the stepped surface may cause deformation or damage of thepiston end surface, giving rise to degradation of the tightness in thecylinder or admittance of air, making it difficult to achieve sufficientsealing function.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to eliminate theabove-mentioned problems and provide a novel accumulator-type liquidsprayer capable of spraying the liquid without leakage of the liquidwithin the cylinder.

According to a first aspect of the present invention, there is providedan accumulator-type liquid sprayer comprising: a cylinder that can besecured to a mouth portion of a container containing a liquid to besprayed, said cylinder having a suction port that is communicated withinside of the container; a hollow stem to which a pressurizing cap canbe secured, said pressurizing cap being operable by a user for sprayingthe liquid from said container; a piston secured to the hollow stem andarranged in the cylinder so as to be slidable according to a pushingforce from the hollow stem and a resilient force from a resilient meansexerted in a direction opposite to said pushing force, said pistondefining a space region within the cylinder; a stopper that is broughtinto contact with an end portion of the piston for restrictingdisplacement of the piston as it is operated; a discharge valve forbringing said space region into communication with the internal passageof the hollow stem by a returning movement of the piston, so that theliquid is discharged from the space region toward outside; and a suctionvalve for bringing said space region into communication with the suctionport of the cylinder by a pushing movement of the piston, so that theliquid is sucked into the space region; wherein the end portion of thepiston, which can be brought into contact with said stopper, is formedwith an annular recess that extends along an outer peripheral edge ofthe end portion.

With the above-mentioned constitution, the piston arranged in thecylinder is caused to slidingly move by the pushing force from thehollow stem and the resilient force of the resilient means, so as toincrease and decrease the pressure in the space region formed betweenthe piston and the cylinder, to thereby suck and discharge the liquid.In this instance, the displacement amount of the piston in the cylinderis restricted by contact of the end portion of the piston with astopper, such as a stepped surface provided in the cylinder.

On this occasion, the piston end portion is brought into contact withthe stopper at the annular recess formed along the outer peripheral edgeof the end portion, without causing contact between the end portion andthe root portion of the stopper. Therefore, even when the root portionof the stopper has a shape that otherwise tends to cause damages ordeformation of the piston end portion, a positive sealing function canbe achieved since the piston end portion is brought into contact withthe stopper without contacting its root portion, and it is thus possibleto spray the content without leakage of the liquid within the cylinder.

The above-mentioned accumulator-type liquid sprayer may further comprisea cover member for covering an opening of the cylinder with a portion ofthe hollow stem being exposed, wherein the opening is arranged oppositeto the suction port. Here, the cover member is arranged to hold thehollow stem so that the exposed portion of the hollow stem can be pushedand returned, and to integrate each of said members as a module.

In this instance, major mechanisms of the accumulator-type liquidsprayer are integrated as a module, and can thus be secured tocontainers with various configurations. In other words, in addition tothe above-mentioned technical effects obtainer by the accumulator-typeliquid sprayer, it is possible to achieve a further technical effectthat various changes to the product specification can be immediatelyaccommodated.

According to a second aspect of the present invention, there is providedan accumulator-type liquid sprayer comprising: a cylinder that can besecured to a mouth portion of a container through a base member, saidcylinder having a suction port that is communicated with inside of thecontainer; a piston arranged in the cylinder and having a passageextending therethrough in its axial direction; a piston guide extendingthrough the passage in the piston so as to be engageable with, anddisengageable from the piston, said piston guide cooperating with thepiston and the cylinder to form a space region for sucking andpressurizing a liquid; a check valve for opening the suction port of thecylinder only during suction of the liquid; a hollow stem slidablyfitted with an outer side of the piston in a liquid-tight manner andengaging with an end portion of the piston guide; a first resilientmember for urging the piston guide against the piston for maintaining aclosed state of the passage in the piston; a second resilient member forurging the piston against the piston guide for adjusting a sprayingpressure of the liquid; and a stopper arranged in the cylinder, forpositioning the piston before the content is sprayed to provideincreased contact surface pressure so as to maintain the closed state ofthe passage.

With the above-mentioned constitution, it is possible to spray thecontent by a smooth operation with a reduced operating force, withoutcausing leakage of the liquid in the cylinder. The number of componentscan be reduced, resulting in simplification of the assembly steps andcost reduction. All the components may be formed of a plastic materialso as to eliminate requirement for fractional recovery for each materialupon disposal of the sprayer.

In the above-mentioned accumulator-type liquid sprayer, said firstresilient member may be arranged between the piston guide and a bottomwall portion of the space region. The accumulator-type liquid sprayermay further comprise a pressurizing cap secured to a tip end of thehollow stem and having a nozzle for spraying toward outside a liquidthat flows out through an inner space of the hollow stem, wherein thesecond resilient member is arranged between the pressurizing cap and thebase member. Furthermore, the stopper may be comprised of a ring memberthat is formed integrally to the base member and brought into a rear endportion of the piston before spraying the liquid.

It is preferred that the above-mentioned accumulator-type liquid sprayerfurther comprises a stopper that is brought into contact with an endportion of the piston for restricting displacement of the piston as itis operated, wherein the end portion of the piston, which can be broughtinto contact with said stopper, is formed with an annular recess thatextends along an outer peripheral edge of the end portion.

In this instance, the displacement amount of the piston in the cylinderis restricted by contact of the end portion of the piston with thestopper.

On this occasion, the piston end portion is brought into contact withthe stopper at the annular recess formed along the outer peripheral edgeof the end portion, without causing contact between the end portion andthe root portion of the stopper. Therefore, even when the root portionof the stopper has a shape that otherwise tends to cause damages ordeformation of the piston end portion, a positive sealing function canbe achieved since the piston end portion is brought into contact withthe stopper without contacting its root portion, and it is thus possibleto spray the content without leakage of the liquid within the cylinder.

The accumulator-type liquid sprayer according to the second aspect ofthe present invention may further comprise a cover member for coveringan opening of the cylinder with a portion of the hollow stem beingexposed, wherein the opening is arranged opposite to the suction port.Here, the cover member is arranged to hold the hollow stem so that theexposed portion of the hollow stem can be pushed and returned, and tointegrate each of said members as a module.

Specifically, it is preferred that such a module comprises a stopperthat is brought into contact with an end portion of the piston forrestricting displacement of the piston as it is operated, wherein theend portion of the piston, which can be brought into contact with saidstopper, is formed with an annular recess that extends along an outerperipheral edge of the end portion.

With the above-mentioned constitution, major mechanisms of theaccumulator-type liquid sprayer are integrated as a module, and can thusbe secured to containers with various configurations. In other words, inaddition to the above-mentioned technical effects obtainer by theaccumulator-type liquid sprayer, it is possible to achieve a furthertechnical effect that various changes to the product specification canbe immediately accommodated.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more fully described below with referenceto preferred embodiments shown in the accompanying drawings.

FIG. 1 is a sectional view of an accumulator-type liquid sprayeraccording to a first embodiment of the present invention.

FIG. 2 is a partly sectional side view of a module corresponding to thesprayer shown in FIG. 1.

FIGS. 3A and 3B are, respectively, a partly sectional side view of thepiston shown in FIGS. 1 and 2, and a sectional view of the piston endportion in enlarged scale.

FIG. 4 is a partly sectional side view of a conventional piston.

FIGS. 5A and 5B are sectional views showing a state in which the endportion of the piston shown in FIGS. 1 to 3 is brought into contact witha stepped surface provided in the cylinder, as well as a state in whichthe end portion of the conventional piston shown in FIG. 4 is broughtinto contact with a stepped surface provided in the cylinder,respectively.

FIG. 6 is a sectional view of an accumulator-type liquid sprayeraccording to a second embodiment of the present invention, which usesthe module shown in FIG. 1.

FIG. 7 is a sectional view of an accumulator-type liquid sprayeraccording to a third embodiment of the present invention.

FIG. 8 is a sectional view of an accumulator-type liquid sprayeraccording to a fourth embodiment of the present invention.

FIG. 9 is a sectional view showing the sprayer of FIG. 8 in a pushedstate.

FIG. 10 is an explanatory view explaining the manner of spraying in thesprayer of FIG. 8.

FIG. 11 is a sectional view of an accumulator-type liquid sprayeraccording to a fifth embodiment of the present invention.

FIG. 12 is a sectional view of an accumulator-type liquid sprayeraccording to a sixth embodiment of the present invention.

FIG. 13 is a sectional view of an accumulator-type liquid sprayeraccording to a seventh embodiment of the present invention.

FIG. 14 is a sectional view of a module corresponding to the sprayer ofFIG. 8.

FIG. 15 is a sectional view of a module corresponding to the sprayer ofFIG. 11.

FIG. 16 is a sectional view of a module corresponding to the sprayer ofFIG. 12.

FIG. 17 is a sectional view of a module corresponding to the sprayer ofFIG. 13.

BEST MOPDE FOR CARRYING OUT THE INVENTION

With reference to the drawings, an accumulator-type liquid sprayeraccording to the present invention will be described hereinafter.

FIG. 1 is a sectional view of an accumulator-type liquid sprayeraccording to a first embodiment of the present invention, and FIG. 2 isa partly sectional side view of a module used in the accumulator-typeliquid sprayer 1 shown in FIG. 1.

In FIG. 1, reference numeral 10 denotes a container to be filled with acontent, reference numeral 11 denotes a mouth portion of the container10, and reference numeral 100 denotes a module that is shown in FIG. 2.

As shown in FIG. 2, the module is comprised of nine parts, i.e., acylinder 110. a piston 120, a piston guide 130, a check valve 140, ahollow stem 150, a first resilient member in the form of a spring 160, asecond resilient member in the form of a spring 170, a cover member 180and a seal element P.

The cylinder 110 has a seat portion 111 f arranged adjacent to a suctionport 111 for receiving a ball 141 thereon, and a plurality of ribs 112for restricting the displacement of the ball 141. The spring 160 isarranged on the upper surfaces 112 f of these ribs 112 to hold one end131 of the piston guide 130. The other end 132 of the piston guide 130is integrally secured to a plurality of ribs 152 formed at internalpassage 151 of the hollow stem 150. These ribs 152 are spaced apart soas to form an annular internal passage 153 that is communicated with theinternal passage 151.

The piston 120 cooperates with the cylinder 110 to define a space region(pump chamber R) therebetween. The piston 120 is slidably held, throughits base portion 121, by a part 151 f of the internal passage 151 formedin the hollow stem 150. The piston 120 has an internal passage 122through which the piston guide 130 extends. The internal passage 122 hasa part 122 f that is brought into sliding contact with an outerperipheral portion 133 of the piston guide 130 by the spring 170arranged between the piston 120 and a flange 154 of the hollow stem 150.By this, the piston 120 is permitted to slide along the inner wallsurface 110 f of the cylinder 110 through its front end portion 123 andrear end portion 124, with a pushing motion induced by a pushing forceF1 fron the hollow stem 150, and a return motion induced by a resilientforce F2 that is applied by the spring 160 via the piston guide 130.

Therefore, when the hollow stem is pushed forward to pressurize the pumpchamber R, the piston 120 and the piston guide 130 are separated fromeach other to communicate the pump chamber R with atmosphere via theinternal passages 122, 153 and 151. On the other hand, when the piston120 is pushed back to depressurize the pump chamber R, the ball 141 isseparated from the seat portion 111 f adjacent to the suction port 111against its own weight, to open the pump chamber R.

In this way, the piston 120 and the piston guide 130 form a dischargevalve that is opened by the pushing motion of the piston 120 induced bythe pushing operation of the hollow stem 150 to discharge the liquidwithin the pump chamber R toward atmosphere, while the seat portion 111f, the ribs 112 and the ball 142 form a suction valve that is opened bythe pushing-back motion of the piston induced by the resilient force ofthe spring 160 to suck the liquid into the pump chamber.

The seal element P is fitted in the groove portion 115 that is undercutalong the outer periphery of the cylinder 110. The cover member 180 inits upper portion has a through hole 182 through which the hollow stemextends, and is provided with an inner wall 183 for fitting the openingportion 114 of the cylinder 110 in cooperation with the inner surface180 f. Thus, at a position where the cover member 180 is in contact withthe seal element P, the cover member 180 seals the opening portion 114of the cylinder 110 and restricts the movement of the hollow stem 150applied with the resilient force of the spring 170 by causing the flangeportion 154 of the hollow stem 150 to contact with the inner wall 182 fof the through hole 182. In this way, the cover member 180 covers theopening portion 114 of the cylinder 110 with the hollow stem 150 partlyexposed, and holds the hollow stem 150 allowing the latter to be pushedand returned.

The accumulator-type liquid sprayer 1 shown in FIG. 1 is of a so-calledspray-type using the above-mentioned module 100, wherein the hollow stem150 exposed from the cover member 180 is provided with a pressurizingcap 13 containing a nozzle tip Es. The liquid sprayer 1 is secured tothe mouth portion 11 of the container 10 through a base member 190 inthe form of a metal screw cap. The pressurizing cap 13 has an ornamentalcap cover 13 c.

The cover member 180 has an outer peripheral portion that is integrallyprovided with a flange portion 184. Thus, as shown in FIG. 1, by layingthe metal screw cap 190 over the upper portion 181 and the flangeportion 184 of the cover member 180 and subsequently causing shrinkagethereof, it is possible to achieve a screw connection of theaccumulator-type liquid sprayer 1 to the mouth portion 11 of thecontainer 10. In this instance, it is possible to achieve a costreduction since adhesive or connector elements for the connection withthe cover member 180 is not required.

The operation of the accumulator-type liquid sprayer 1 in conjunctionwith the module 100 will be explained below.

When the pressurizing cap 13 is manually depressed down, the hollow stem150 is initially pushed in the direction indicated by arrow F1 as shownin FIG. 2. In cooperation with the pushing operation of the hollows stem150, the piston 120 is pushed within the cylinder 110 against theresilient force of the spring 160 to pressurize the inside of the pumpchamber R.

Then, since the pressure within the pump chamber P is increased, thepiston 120 and the piston guide 130 are separated from each otheragainst the resilient force of the spring 160, leaving the ball 141seated on the seat portion 111 f, so as to discharge the liquid withinthe pump chamber R toward outside from the nozzle Es of the pressurizingcap 13, via the internal passage 122 of the piston and the internalpassages 153 and 151 of the hollow stem. Subsequently, the piston 120and the piston guide 130 are brought into a sealing contact by theresilient force of the spring 160. When the user's hand is thereafterreleased from the pressurizing cap 13 to interrupt the pushing operationwith respect to the hollow stem 150, the piston 120 is pushed backthrough the piston guide 130 by the resilient force of the spring 160 togenerate a negative pressure within the pump chamber R. Thus, the ball141 is separated from the seat portion 111 f against its own weight,maintaining a sealing contact between the piston 120 and the pistonguide 130, so as to suck the liquid from outside and introduce it intothe pump chamber R.

Subsequently, by repeating the pushing operation of the hollow stem 150through the pressurizing cap 13, the pressure of the liquid filling thepump chamber R is increased and decreased so that the discharge valvecomprised of the piston 120 and the piston guide 130 and the suctionvalve 140 comprised of the ball 141 are alternately operated to suck theliquid from outside and discharge the liquid from the nozzle Es of thepressurizing cap 13 through the internal passage 151 in the hollow stem150.

In the accumulator-type liquid sprayer 1 and the module 100 thereof, thepushing motion of the piston 120 is restricted as the front end portion123 of the piston 120 is brought into contact with the stepped surface113 formed in the cylinder 110.

FIGS. 3A and 3B are, respectively, a partly sectional side view of thepiston 120 and a sectional view of the piston end portion 123 inenlarged scale. FIG. 4 is a partly sectional side view of a conventionalpiston 20. FIGS. 5A and 5B are sectional views showing a state in whichthe end portion 123 of the piston 120 is brought into contact with astepped surface 113 formed in the cylinder 110, as well as a state inwhich the end portion 23 of the conventional piston 20 is brought intocontact with a stepped surface 113 formed in the cylinder 113,respectively.

As shown in FIGS. 3A and 3B, the piston 120 has a front end portion 123on its lower side, which is formed with an annular stepped recess 123 athat divides the end portion 123 into a sliding surface 123 f 1 slidablyengageable with the inner wall surface 110 f of the cylinder and acontact surface 123 f 2 that can be brought into contact with thestepped surface 113.

With the module 100 and the accumulator-type liquid sprayer 1 using thesame, the piston 120 arranged in the cylinder 110 is caused to slidinglymove by the pushing force F1 from the hollow stem 150 and the resilientforce F2 of the spring 160, so as to increase and decrease the pressurein the pump chamber R between the piston 120 and the cylinder 110, tothereby suck and discharge the liquid. In this instance, thedisplacement amount of the piston 120 in the cylinder 110 is restrictedby contact of the end portion 123 of the piston 120 with the steppedsurface 113 provided in the cylinder 110.

On this occasion, as shown in FIG. 5A, the front end portion 123 of thepiston 120 is brought into contact with the stepped surface 113 f at theannular recess 123 a formed along the outer peripheral edge of the endportion, without causing contact between the end portion and the rootportion 113 a of the stepped surface 113.

In contrast, in the case of the conventional piston 20, its end portion23 has a substantially flat contact surface 23 f and is thus broughtinto contact with the root portion 113 a of the stepped surface 113, asshown in FIG. 5B, thereby causing deformation or damage of the pistonend surface and giving rise to degradation of the sealing function,depending upon the shape of the root portion 113 a.

Therefore, with the module 100 and the accumulator-type liquid sprayer 1using the same, even when the root portion 113 a of the stepped surface113 has a shape that otherwise tends to cause damages or deformation ofthe front end portion 123 of the piston 120, a positive sealing functioncan be achieved since the front end portion 123 of the piston 120 isbrought into contact with the stepped surface 113 without contacting itsroot portion 113 a, and it is thus possible to spray the content withoutleakage of the liquid within the cylinder.

The module 100 is to modularize the major mechanisms of theaccumulator-type liquid sprayer 1 into an integrated assembly so that itcan be secured to elements having various configurations. Therefore, inaddition to the technical effects obtainer by the accumulator-typeliquid sprayer 1, the module 100 makes it possible to achieve a furthertechnical effect that various changes to the product specification canbe immediately accommodated. Incidentally, the annular recess 123 a isnot limited in shape to the above-mentioned stepped recess, but also maybe a recess wherein the sliding surface 123 f 1 and the contact surface123 f 2 forming the lower end portion are connected to each other by astraight line or a curved line.

FIG. 6 is a sectional view of the accumulator-type liquid sprayeraccording to a second embodiment of the present invention, which alsouses the module 100. Elements shown in FIGS. 1 to 5 are denoted by thesame reference numerals and explanation thereof is omitted.

The accumulator-type liquid sprayer 2 shown in FIG. 6 is of spray-typesimilar to that shown in FIG. 1, which is secured to the mouth portion11 of the container 10 through a base member 191, though the head cover13 c is detachably secured to the base member 191.

In the case of the accumulator-type liquid sprayer 2 also, the covermember 180 has an outer peripheral portion integrally provided with aflange portion 184. Therefore, it can be secured to the moth portion 11of the container 10 simply by undercut fitting the base member 191 withthe flange portion 184 of the cover member 180, and it is thus possibleto achieve a cost reduction since adhesive or connector elements for theconnection with the cover member 180 is not required.

Incidentally, the accumulator-type liquid sprayer according to theabove-mentioned first aspect of the present invention may be directlysecured to the mouth portion 11 of the container 10 without using themodule 100 such as that shown in FIG. 2.

FIG. 7 is a sectional view of the accumulator-type liquid sprayeraccording to a third embodiment of the present invention. Elements shownin FIGS. 1 to 6 are denoted by the same reference numerals andexplanation thereof is omitted.

The accumulator-type liquid sprayer 3 shown in FIG. 7 is of the typewherein the cylinder 110 is secured to the mouth portion 11 of thecontainer 10 through a base member 192. In this instance also, since thefront end portion 123 of the piston 120 is formed with an annular recess123 a along the outer peripheral edge of the end portion, even when theroot portion 113 a of the stepped surface 113 has a shape that otherwisetends to cause damages or deformation of the front end portion 123 ofthe piston 120, a positive sealing function can be achieved since thefront end portion 123 of the piston 120 is brought into contact with thestepped surface 113 without contacting its root portion 113 a, and it isthus possible to spray the content without leakage of the liquid withinthe cylinder.

Incidentally, in the accumulator-type liquid sprayer 1 to 3 and themodule 100 thereof, only the front end portion 123 of the piston 120 isprovided with an annular recess 123 a in order to restrict thedisplacement amount of the piston 120 by a contact of the front endportion 123 of the piston 120 with the stepped surface 113 when thepiston 120 is pushed. However, when a stopper is provided, which isbrought into contact with the rear end portion 124 of the piston 120 forlimiting its displacement amount, the rear end portion 124 of the piston120 may be provided with an annular recess along its outer peripheraledge.

Now, in the accumulator-type liquid sprayer 1 to 3 and the module 100 asshown in FIGS. 1 to 7, it would be effective to lower the resilientforce of either one of the springs 160, 170, so as to reduce the load tobe applied to the pressurizing cap 13 or the hollow stem 130 uponspraying the content and thereby realize spraying under a smooth pumpingaction. In this instance, however, since the contact pressure betweenthe piston 120 and the piston guide 130 is reduced, liquid leakage mayoccur in the cylinder 110, making it difficult to achieve an efficientspraying of the content.

Therefore, with reference to the drawings, there will be described belowa novel accumulator-type liquid sprayer that allows a smooth spraying ofthe liquid under a low load without causing liquid leakage within thecylinder.

FIG. 8 is a sectional view of the accumulator-type liquid sprayeraccording to a fourth embodiment of the present invention. In theaccumulator-type liquid sprayer 4 shown in FIG. 8, reference numeral 10denotes a container to be filled with content, and reference numeral 11denotes a mouth portion of the container 10.

Reference numeral 210 denotes a cylinder that is secured to the mouthportion 11 of the container 10 through a base member 290. The cylinder210 has a bottom wall portion that is formed with a suction port 210 afor sucking the content through a suction tube 14. The base member 290is exemplarily shown as having an opening that is in communication withinside of the container 10, and as being threadedly secured to the mouthportion.

Reference numeral 220 denotes a piston that is arranged in the cylinder210. The piston 220 has an internal passage 220 a extending therethroughin its axial direction.

Reference numeral 230 denotes a piston guide. This piston guide 230 isarranged to extend through the internal passage 220 a of the piston 220and serves to open or close the internal passage 220 a, and cooperateswith the cylinder 210 and the piston 220 to define a space region (pumpchamber) R for sucking and pressurizing the liquid.

Reference numeral 240 denotes a check valve that opens the suction port210 a only when the liquid is sucked, and reference numeral 250 denotesa hollow stem. The hollow stem 250 is slidably fitted over the outerside of the piston 220 in a liquid-tight manner and engaged with the endportion 232 of the piston guide 230.

Reference numeral 13 denotes a pressurizing cap that is secured to thetip end of the hollow stem 250. The pressurizing cap 13 includes anozzle Es for discharging fluid, such as air or liquid, to outsidethrough the internal passage 250 a of the hollow stem 250.

Reference numeral 260 denotes a first resilient member. The firstresilient member 260 is arranged in the pump chamber R within thecylinder 220, and serves to urge the piston guide 230 against the piston220 to thereby maintain a closed state of the passage 220 a of thepiston 220.

Reference numeral 270 denotes a second resilient member. This resilientmember 270 is exemplarily shown as being arranged between the piston 220and the hollow stem 250, and serves to urge the piston 220 against thepiston guide 230 to thereby adjust the spraying pressure (internalpressure) of the content.

Reference character S denotes a stopper that is exemplarily shown asbeing integrally formed with the base member 290 as its inner ring. Thestopper S is brought into contact with the rear end portion 224 of thepiston 220 to thereby position the piston 220 before spraying thecontent. Incidentally, the pushing motion of the piston 220 isrestricted when the front end portion 223 of the piston 220 is broughtinto contact with the stepped surface 213, since the stepped surface 213provided in the cylinder 210 functions as a stopper.

The passage 220 a in the piston 220 is maintained in a closed state byurging the piston 220 and the piston guide 230 in opposite directions bymeans of the first and second resilient members 260 and 270. When,however, the resilient force of the second resilient member 270 isdecreased to allow a smooth spraying of the content, the urging force ofthe piston 220 relative to the piston guide 230 is decreased to degradethe sealing property of the passage 220 a in the closed state, therebygiving rise to an internal leakage.

According to the present embodiment, the stopper S is brought intocontact with the rear end portion 242 of the piston for positioning thesame, so that the urging force of the first resilient member 260 appliedto the piston 220 is maintained constant even when the resilient forceof the second resilient member 270 is changed. It is thus possible toensure a smooth spraying of the content without degrading the sealingproperty in the closed state of the passage 220 a.

While the stopper S has been exemplarily shown as being integrallyformed with the base member 290, it may be formed as a separate memberor, alternatively, molded integrally with the cylinder 210 like thestepped surface 213, if not particularly problematic from the viewpointof production technology.

The first resilient member 260 and the second resilient member 270 maybe comprised of helical coil springs, though the shape is notparticularly limited provided that a desired resilient force can beassured. These resilient members may be comprised of plastics, thoughthey may be alternatively comprised of metal if not hazardous in termsof the quality of the content.

As shown in FIG. 9, when a load is applied to the upper surface of thepressurizing cap 13 to push down the piston 220 together with the hollowstem 250, and the load is thereafter removed, the hollow stem and thepiston 220 are returned to the initial positions under the restoringforce of the first resilient member 260. On this occasion, the spaceregion R is depressurized so that the content within the container 10 isintroduced into the space region R through the suction tube 14 and thesuction port 210 a.

In this condition, when the upper surface of the pressurizing cap 13 isapplied with a load to push down the piston 220 together with the hollowstem 250, as shown in FIG. 10, the suction port 210 a is closed by thecheck valve 240 so that the pressure in the space region R increases. Onthe other hand, in terms of the relation between the piston 220 and thehollow stem 250, the passage 220 a is opened until the inner end 250 bof the hollow stem 250 comes into abutment with the end surface 220 b ofthe piston 220, so that the content under the increased inner pressureis passed through the internal space 250 a of the hollow stem 250 andsprayed to outside from the nozzle Es of the pressurizing cap 13.

By repeated application of the load to the pressurizing cap 13,therefore, the content is continuously sprayed and a pressurizing mediumindispensable in the aerosol-type sprayer is not required.

In the embodiment shown in FIG. 8, each element may be comprised ofplastics. In particular, as shown in FIG. 11, when the first and secondresilient members are formed as unitary members that are integrallyformed with the piston guide 230 and the hollow stem 250, respectively,it is possible advantageously to reduce the number of components.

FIG. 12 is a sectional view of the accumulator-type liquid sprayeraccording to a sixth embodiment of the present invention. Thisaccumulator-type liquid sprayer 6 is a modification of the embodimentsshown in FIGS. 8 to 10, and comprises a piston 220 having front and rearend portions 223 and 224, which are respectively formed with annularrecesses 223 a, 224 a extending along the outer peripheral edges.

In this instance, the displacement amount of the piston 220 within thecylinder 210 is restricted by contact of the front end portion 223 ofthe piston 220 with the stepped surface 213 provided in the cylinder210, and further by a contact of the rear end portion 224 of the piston220 with the stopper S formed integrally with the base member 290.

On this occasion, the front end portion 223 and the rear end portion 224of the piston 220 are brought into contact with the stepped surface 213and the stopper S, respectively, without contacting the root portions ofthe stepped surface 213 and the stopper S. Thus, even when the rootportions of the stepped surface 213 or the stopper S has a shape thatotherwise tends to cause damages or deformation of the front end portion223 or the rear end portion 224 of the piston 120, a positive sealingfunction can be achieved since the front end portion 223 or the rear endportion 224 of the piston 220 is brought into contact with the steppedsurface 213 or the stopper S without contacting the root portion of thestepped surface 213 or the stopper S, and it is thus possible to spraythe content without leakage of the liquid within the cylinder.

FIG. 13 is a sectional view of the accumulator-type liquid sprayeraccording to a seventh embodiment of the present invention. Thisaccumulator-type liquid sprayer 7 combines the fifth and sixthembodiments of FIGS. 11 and 12, and comprises a piston 220 having frontand rear end portions 223 and 224, which are respectively formed withannular recesses 223 a, 224 a extending along the outer peripheraledges. This embodiment is essentially the same as the sixth embodimentexcept the structure of the first and second resilient members.

Incidentally, the accumulator-type liquid sprayers 4 to 7 according tothe present invention may be formed as modules 200 to 500 shown in FIGS.14 to 17, wherein all elements are integrated as an assembly.

As shown in FIGS. 14 to 17, the modules 200 to 500 each comprises a sealelement P that is fitted in an undercut groove 215 formed in the outerperiphery of the cylinder 210. The cover member 280 in its upper portionhas a through hole 282 through which the hollow stem extends, and isprovided with an inner wall 283 for fitting the opening portion 214 ofthe cylinder 210 in cooperation with the inner surface 280 f.

Thus, at a position where the cover member 280 is in contact with theseal element P, the cover member 280 seals the opening portion 214 ofthe cylinder 210 and restricts the movement of the hollow stem 250applied with the resilient force of the spring 270 by causing the flangeportion 254 of the hollow stem 250 to contact with the inner wall 282 fof the through hole 282. In this way, the cover member 280 covers theopening portion 214 of the cylinder 210 with the hollow stem 250 partlyexposed, and holds the hollow stem 250 allowing the latter to be pushedand returned.

In the embodiments shown in FIGS. 14 to 17 also, the cover member 180has an outer peripheral portion integrally provided with a flangeportion 184. Therefore, it can be secured to the moth portion 11 of thecontainer 10 by using a base member 190, 191 as shown in FIG. 1 or FIG.6.

In the modules shown in FIGS. 14 to 17 also, a stepped surface 213 isprovided in the cylinder 210 and the inner wall 283 is provided with astopper S that is integral with the cover member 280 as an inner ring.Therefore, as in the accumulator-type liquid sprayers 6 and 7 and themodules 400 and 500 thereof, it is preferred that the annular recesses223 a, 224 a provided for the piston 220 are formed in the front endportion 223 and the rear end portion 224 of the piston 220,respectively, though such annular recess may be provided for only one ofthe front end portion 223 and the rear end portion 224 of the piston220.

The present invention has been described above with reference to thepreferred embodiments and it is apparent to a skilled person thatvarious modifications may be made without departing from the scope ofthe invention. For example, instead of a spray-type using a nozzle tip,the accumulator-type liquid sprayer may be of a type in which highlyviscous fluid, such as emulsion, is directly discharged. Also, theaccumulator-type liquid sprayer may be of a type in which a cleansingcream is discharged onto a cotton or puff by depressing a tray-likenozzle head provided for the piston.

The components of the sprayer can be each produced by injection moldingor the like, though the present invention is not limited to a particularproduction method.

In this connection, there may be used polyethylene, polypropylene,nylon, ABS resin or the like, besides polyethylene terephthalate (PET),polybuthylene terephthalate (PBT) or polyoxymethylene (POM) which areexcellent in chemical resistance.

1. An accumulator-type liquid sprayer comprising: a cylinder that can besecured to a mouth portion of a container containing a liquid to besprayed, said cylinder having a suction port that is communicated withinside of the container; a hollow stem to which a pressurizing cap canbe secured, said pressurizing cap being operable by a user for sprayingthe liquid from said container; a piston secured to the hollow stem andarranged in the cylinder so as to be slidable according to a pushingforce from the hollow stem and a resilient force from a resilient meansexerted in a direction opposite to said pushing force, said pistondefining a space region within the cylinder; a stopper that is broughtinto contact with an end portion of the piston for restrictingdisplacement of the piston as it is operated; a discharge valve forbringing said space region into communication with the internal passageof the hollow stem by a returning movement of the piston, so that theliquid is discharged from the space region toward outside; and a suctionvalve for bringing said space region into communication with the suctionport of the cylinder by a pushing movement of the piston, so that theliquid is sucked into the space region; the end portion of the piston,which can be brought into contact with said stopper, being formed withan annular recess that extends along an outer peripheral edge of the endportion.
 2. The accumulator-type liquid sprayer according to claim 1,further comprising a cover member for covering an opening of thecylinder with a portion of said hollow stem being exposed, said openingbeing arranged opposite to said suction port, said cover member holdingsaid hollow stem so that said exposed portion of the hollow stem can bepushed and returned, and said cover member integrating each said membersas a module.
 3. An accumulator-type liquid sprayer comprising: acylinder that can be secured to a mouth portion of a container through abase member, said cylinder having a suction port that is communicatedwith inside of the container; a piston arranged in the cylinder andhaving a passage extending therethrough in its axial direction; a pistonguide extending through the passage in the piston so as to be engageablewith, and disengageable from the piston, said piston guide cooperatingwith the piston and the cylinder to form a space region for sucking andpressurizing a liquid; a check valve for opening the suction port of thecylinder only during suction of the liquid; a hollow stem slidablyfitted with an outer side of the piston in a liquid-tight manner andengaging with an end portion of the piston guide; a first resilientmember for urging the piston guide against the piston for maintaining aclosed state of the passage in the piston; a second resilient member forurging the piston against the piston guide for adjusting a sprayingpressure of the liquid; and a stopper arranged in the cylinder, forpositioning the piston before the content is sprayed to provideincreased contact surface pressure so as to maintain the closed state ofthe passage.
 4. The accumulator-type liquid sprayer according to claim3, wherein said first resilient member is arranged between the pistonguide and a bottom wall portion of the space region.
 5. Theaccumulator-type liquid sprayer according to claim 3, further comprisinga pressurizing cap secured to a tip end of the hollow stem and having anozzle for spraying toward outside a liquid that flows out through aninner space of the hollow stem, and wherein said second resilient memberis arranged between the pressurizing cap and the base member.
 6. Theaccumulator-type liquid sprayer according to claim 3, wherein saidstopper is comprised of a ring member that is formed integrally to thebase member and brought into a rear end portion of the piston beforespraying the liquid.
 7. The accumulator-type liquid sprayer according toclaim 3, further comprising a stopper that is brought into contact withan end portion of the piston for restricting displacement of the pistonas it is operated, wherein the end portion of the piston, which can bebrought into contact with said stopper, is formed with an annular recessthat extends along an outer peripheral edge of the end portion.
 8. Theaccumulator-type liquid sprayer according to claim 3, further comprisinga cover member for covering an opening of the cylinder with a portion ofsaid hollow stem being exposed, said opening being arranged opposite tosaid suction port, said cover member holding said hollow stem so thatsaid exposed portion of the hollow stem can be pushed and returned, andsaid cover member integrating each said members as a module.
 9. Theaccumulator-type liquid sprayer according to claim 8, further comprisinga stopper that is brought into contact with an end portion of the pistonfor restricting displacement of the piston as it is operated, whereinthe end portion of the piston, which can be brought into contact withsaid stopper, is formed with an annular recess that extends along anouter peripheral edge of the end portion.